What's the vulnerability?

A sandbox escape vulnerability allows sandboxed code to mutate host built-in prototypes by laundering the isGlobal protection flag through array literal intermediaries. When a global prototype reference (e.g., Map.prototype, Set.prototype) is placed into an array and retrieved, the isGlobal taint is stripped, permitting direct prototype mutation from within the sandbox. This results in persistent host-side prototype pollution and may enable RCE in applications that use polluted properties in sensitive sinks (example gadget: execSync(obj.cmd)).

Root Cause Analysis
One Command

Verify with pruva-verify

Run the Pruva CLI to automatically fetch and execute the reproduction script.

pruva-verify REPRO-2026-00098
or pruva-verify GHSA-ww7g-4gwx-m7wj
or pruva-verify CVE-2026-25881
Install: curl -fsSL https://pruva.dev/install.sh | sh

Or Run Manually

1

Download the script

curl -O https://pruva.dev/api/v1/reproductions/REPRO-2026-00098/artifacts/repro/reproduction_steps.sh
2

Make executable

chmod +x reproduction_steps.sh
3

Run the script

./reproduction_steps.sh
Run in a VM, container, or disposable environment. This exploits a real vulnerability.

How Pruva Reproduced This

Watch the AI agent's step-by-step process.

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